BOM: Deliberate Hiding of Varying Temperature Recordings By James Reed

More on the failing climate change agenda; Dr Jennifer Marohasy has investigated discrepancies in temperature data of the Bureau of Meteorology (BOM). The discrepancies arose when the BOM switched its temperature reading instruments from mercury thermometers to platinum resistance probes. The issue is technical, but it seems that the platinum probes “run hot,” giving higher temperature. So, it would throw out the predictions. Here is a common-sense summary from the IPA, with further more technical material from The Australian.

 

This sort of critique is necessary to begin undermining the climate change agenda.

“This week, I want to share an IPA achievement that brings home how our research can sometimes take a long time to come to fruition – in this case, more than a decade. I am talking about IPA Senior Fellow Dr Jennifer Marohasy’s decade-long investigation into discrepancies in temperature data of the Bureau of Meteorology (BOM). The discrepancies arose when the BOM switched its temperature reading instruments from mercury thermometers to platinum resistance probes across its various weather stations in Australia. This week, The Australian published the results of her research based on more than 1,000 pages of temperature data – finally released to Dr Marohasy by the BOM under considerable duress just before Easter – which irrefutably show that new probes can record different temperatures to mercury thermometers in the same location at the same time. Significantly, Jennifer’s research into the data released shows that 41 per cent of the time, the probes returned temperatures higher than the mercury thermometers. In one instance, the probe at the BOM’s Brisbane Airport site read the temperature 0.7C warmer that the traditional thermometer. The reason why the discrepancy is so significant is because the BOM has, in the interim, made several sensational claims of temperature records being broken at its stations, all the while comparing temperatures recorded using probes with historical temperatures recorded using mercury thermometers. Jennifer’s research was also discussed in a strongly worded editorial by The Australian. The editorial questioned the BoM’s consistent refusal to share its temperature data in response to Freedom of Information requests by IPA Senior Fellow John Abbot. Eventually, John challenged the BOM’s decision at the Administrative Appeals Tribunal. Even then, it has only released partial data. The editorial pointed out the irony of the BOM claiming the data was of no public interest while simultaneously making public announcements that a temperature increase of 1.5C would devastate the planet. The editorial concludes:

 

The Bureau of Meteorology is a public institution and the information it holds is the property of the public. Parallel data records should be made immediately available alongside all the other data the bureau prides itself on making public. There should also be a proper, expert appraisal of what the information says, whether it has been collected as fully as it should have been, and whether the bureau is indeed following world’s best practice in the use of platinum resistance probes, as it says it is, despite World Meteorological Organisation’s advice to the contrary.

 

Jennifer’s research has also been discussed by former chair of the ABC, Maurice Newman, in The Australian, and Jennifer discussed the findings of her research on the shows, Outsiders and Chris Kenny Tonight, on Sky News Australia.”

 

https://www.theaustralian.com.au/science/measure-of-contention-as-mercury-rises-in-bureau-of-meteorology-probe-row/news-story/1fd6f762b7ea449aee7b0b3e5fe75382

 

“A dispute over how the Bureau of Meteorology records daily temperatures is hotting up, with the release of more than 1000 pages of data that show new probes can record different temperatures to mercury thermometers in the same location at the same time.

The documents, released after a years-long Freedom of Information campaign, show temperature measurements taken using updated BOM probes in automatic weather stations at the Brisbane Airport site could be up to 0.7C warmer than the temperature taken using a traditional thermometer at the same time at the same site.

More than three years after a FOI request for parallel data was lodged by scientist John Abbot, the BOM released three years of data on Easter eve after the matter was taken to the Administrative Appeals Tribunal.

In the end, the BOM released only limited data, paving the way for a wave of FOI demands that full records be released in the public interest.

Release of the data is the first opportunity to analyse the performance of BOM probes alongside mercury thermometers. The bureau has long claimed the readings are identical but critics have said the BOM was not following World Met­eor­­ological Organisation guidelines on how they should be used.

Given that even small variations in temperature recordings can have an impact on the long-term record, accuracy is vital.

The main issue is how well temperatures recorded by new technologies can be compared to earlier methods to establish a continuous record.

The BOM maintains that an assessment of the full 2019-22 period at Brisbane Airport finds no significant difference between the probe and mercury thermometers.

Yet analysis of the data by scientist Jennifer Marohasy has found a statistically significant difference exists. Over the three-year period for which records have been made available, probes returned temperatures higher than the mercury thermometers placed alongside them 41 per cent of the time.

Recordings were the same 32.8 per cent of the time and lower 25.9 per cent of the time.

Dr Marohasy said the BOM had not disputed that the probe at Brisbane Airport had recorded up to 0.7C warmer than the ­mercury at the same site at the same time.

She said the bureau had not provided comment on the ­actual difference daily between temperatures as measured by the probe and the mercury, nor the average monthly or annual difference between the probe and the mercury.

In response to questions from The Weekend Australian, the ­bureau said it “verifies temperature probes to ensure that they are within specification”. The BOM said the temperature measurement system at Brisbane Airport was verified 24 times between January 2008 and July last year.

“Probes undergo a verification test in situ to ensure the probe is operating within specification”, it said. “If the result of this test is that the probe is outside of its operating specification, it is replaced with a laboratory-verified probe.

“A second verification test is undertaken to ensure it is compliant with the specification.

“This verification process is more rigorous and reliable than recalibration.”

 

The documents released by the BOM under the FOI request included 1094 A8 reports with the handwritten daily maximum and minimum temperatures from both probes and traditional ­liquid-in-glass thermometers recorded from instruments in the same shelter/Stevenson screen.

They represent about 20 per cent of the parallel records held for the Brisbane airport site, one of 38 sites originally requested under FOI.

Dr Marohasy said analysis of the Brisbane airport data proved the BOM claim that the new probes had been specially developed to measure exactly the same temperatures as the mercury thermometers was wrong. Dr Marohasy has had a years long dispute with the BOM over the accuracy of the new probes and what she says is a failure by it to adhere to WMO guidelines to average the data recorded and maintain mercury thermometers alongside new technologies for an extended period.

“Readings from the probe are taken every second, and the highest value in a 24-hour period becomes the maximum temp­erature for that day. WMO guidelines recommend that instantaneous readings from probes be averaged over at least one minute”, she said.

Dr Marohasy said the difference in readings between probes and mercury thermometers was significant.

“Given new ‘hottest ever’ days are often called and make newspaper headlines when the temperature is only some fractions of a degree warmer, future new record hot days could be a consequence of the probe rather than global warming”.

“This has implications for the artificial generation of new record hot temperatures”, she said.

The other key issue was that Brisbane Airport parallel data showed a dramatic change in the difference between the mercury and probe temperature readings after December 2019.

“It is important to know whether this average difference of 0.35C had been caused by a recalibration of the probe that is the official recording instrument at Brisbane Airport”, she said.

Dr Abbot said he would request further parallel data sets from the BOM and was hopeful that previous barriers to access in regard of the existence of these records and costs would not reoccur. “Under FOI legislation, fee waivers should be granted as the information derived is clearly in the public interest” Dr Abbot said.

“We hope previous assertions from the BOM that analysis of parallel temperature data is only of benefit to John Abbot personally and has no public interest will not reoccur,” he said.

“The public is constantly being told of impending global catastrophe should temperatures rise by more than 1.5C. Discrepancies of more than 0.5C because of instrumentation differences are therefore very significant, and certainly should satisfy the public interest test”, Dr Abbot said.

“Different measuring instruments have been used to record temperatures at Brisbane Airport. Given the importance of reliable continuous records, it is important to know whether these instruments are recording the same temperatures, or not. The parallel data so far made available constitutes only a small portion of what the BOM holds.

“It is important to extend the analyses to longer periods and for other geographical locations.”

Dr Abbot first requested the parallel data for Brisbane Airport on December 12, 2019.

The case eventually went before the AAT on February 3, 2023, and was subsequently resolved with the bureau agreeing to provide three years of data.

Dr Marohasy said the data represented just three of the 14.5 years (January 2008 to July 2022) of parallel data that the bureau held for Brisbane Airport.

“It is also just a fraction of the 760 years of parallel data the bureau holds for 38 different locations spread across the landmass of Australia,” she said.

Probes in automatic weather stations began replacing mercury thermometers across Australia and the world 30 years ago.

Dr Marohasy said the probes were generally more sensitive to changes in temperature, so they could measure extremes of temperatures that traditional mercury thermometers with slower response times could not detect.

Most meteorological offices tried to achieve equivalence between the probes and mercury by averaging instantaneous recordings from probes over 1-5 minutes.

Dr Marohasy said the BOM adopted took instantaneous readings every second from custom-designed probes with longer time constants purported to mimic mercury thermometers.

The bureau has claimed in correspondence with Dr Marohasy that it never averaged measurements from probes.

Bureau chief executive Andrew Johnson has told her the probes were specifically designed to have a long response time to mirror the behaviour of mercury in glass, making numerical averaging unnecessary.

Dr Marohasy said the lack of numerical averaging despite the use of probes made the BOM measurements unique in the world.

She said equivalence was important for the construction of reliable historical temperature datasets, for understanding temperature trends and for knowing whether a record hot day as measured automatically by a probe­­ ­really was hotter than what might have been read manually from a mercury thermometer.”

 

https://www.theaustralian.com.au/commentary/editorials/temperature-data-must-be-public/news-story/9c4129a15714384d9226f56b6f7e9533